Vice President Joe Biden and U.S. Rep. Paul Ryan, the two men who hope to be vice president for the next four years, faced off in a testy, quarrelsome debate on Thursday, repeatedly interrupting each other as they argued on an array of issues, from the deadly attack on the U.S. consulate in Libya and preventing nuclear war with Iran to cutting taxes and creating jobs.

In their first and only campaign debate, Biden and Ryan battled for the last word on each topic, as they accused each other of misleading voters on their plans to steer the economy from the doldrums and boost America's standing abroad.

Biden, 69, a former U.S. senator who once chaired the Senate Foreign Relations Committee, was the clear aggressor. He broke out into toothy smiles and often laughed while Ryan spoke. Biden frequently referred to the 42-year-old Wisconsin congressman, who chairs the House Budget Committee, as "my friend."

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Biden seemed to be trying to make up for the passive performance by his running mate, President Barack Obama, in a debate against Mitt Romney last week.

Ryan called him on that at one point, saying, after one of Biden's interruptions: "Mr. Vice President, I know you're under a lot of duress to make up for lost ground, but I think people would be better served if we don't keep interrupting each other."

Ryan, meanwhile, gave as well as he got, countering Biden's dismissive attacks by accusing the Obama administration of failing to follow through on its promises at the outset of its term.

Biden cut him off and interjected: "With all due respect, that's a bunch of malarkey."

The verbal skirmishes were made more dramatic by the candidates' proximity to each other: they sat a couple of feet apart, at a desk with moderator Martha Raddatz, ABC News’ senior foreign affairs correspondent, and facing the audience at Centre College in Danville, Ky.

Biden went into Thursday’s debate needing to stanch the fallout from Obama’s poor performance in the Oct. 3 debate with Romney, who has since gained in the polls and is now within striking distance of the president. Biden’s goal was to not only flatten the Romney ticket’s momentum but also to reignite enthusiasm among disappointed Democrats.

Ryan, on the other hand, entered the debate with the upper hand, politically, and needed to maintain pressure on Biden.

The frenetic parrying began with the opening question, when Raddatz asked Biden if a "massive intelligence failure" was to blame for the consulate attacks, in which Ambassador Chris Stevens and three other Americans were killed.

Biden called it "a tragedy" and promised that the Obama administration would get to the bottom of it. "Whatever mistakes were made will not be made again," Biden said.

Ryan pounced, noting that it took two weeks for the Obama administration to acknowledge that Islamic militants, and not protesters angered by an American-made anti-Muslim video, were to blame for the attacks.

"This Benghazi issue would be a tragedy in and of itself, but unfortunately it's indicative of a broader problem," Ryan said. "And that is what we are watching on our TV screens is the unraveling of the Obama foreign policy."

When the discussion turned to keeping Iran from obtaining a nuclear weapon, Ryan accused the Obama administration of being unable to instill enough fear in Iran's leaders.

"This is a bunch of stuff," Biden said.

"What does that mean, a bunch of stuff?" Raddatz asked.

"Well, it means it's simply inaccurate," Biden replied.

"It's Irish," Ryan offered, prompting laughter.

"It is," Biden said.

"We Irish call it malarkey," Ryan said.

Turning serious again, Biden suggested that the Republicans saw war as the best option and downplayed Iran's ability to produce a warhead. He credited the American-led sanctions that have reportedly crippled the Iranian economy.

"Let's all calm down a little bit here," Biden said. "Iran is more isolated today than when we took office. It was on the ascendancy when we took office. It is totally isolated."

Ryan said those sanctions were passed by Congress over the Obama administration's desire to negotiate more.

"I don't know what world this guy's living in," Biden interjected.

"Thank heavens we had these sanctions in place," Ryan continued. "It's in spite of their opposition."

"Oh, God," Biden sighed.

"They've given 20 waivers to this sanction," Ryan said. "And all I have to point to are the results. They're four years closer toward a nuclear weapon. I think that case speaks for itself."

"I don't know how long it will take," Biden said. "We can and we will get it under 6 percent."

Ryan argued that the Obama administration's economic policies have taken the country "in the wrong direction."

Ryan began to explain Romney's proposal for an across-the-board tax rate cut of 20 percent, funded in part by closing many loopholes and deductions for wealthier Americans. Biden called that "not mathematically possible" without also cutting tax advantages for the middle class.

"Oh, now you're Jack Kennedy?" Biden quipped. It was a reference to a now-famous exchange at the 1988 vice-presidential debate, when Dan Quayle compared himself Kennedy and his opponent, Lloyd Bentsen, admonished, "You're no Jack Kennedy."

Everyone, including Ryan, chuckled.

During that argument on taxes and the economy, Biden also brought up something that Obama failed to last week: That Romney had been caught on tape at a fundraiser talking about the "47 percent" of Americans who he said didn't pay income taxes and were dependent on government entitlements.

"I've had it up to here with this notion (of) that 47 percent," Biden said.

He accused the Republicans of always trying to avoid raising taxes instead of doing whatever was necessary to help the middle class.

"It's about time they take some responsibility here," Biden said.

Ryan, unable to resist a dig at Biden, reminded his gaffe-prone opponent: “I think the vice president very well knows that sometimes the words don't come out of your mouth the right way."

Biden managed to laugh at himself that time. He followed up, “But I always say what I mean. And so does Romney.”

The next presidential debate, between Obama and Romney, will be held Tuesday at Hofstra University in Hempstead, N.Y.